US3779024A - Stationary storage and mooring plant resting on the bottom of the sea - Google Patents

Abstract

A stationary plant for servicing ships comprises a mooring structure resting on the bottom of the sea and projecting upwardly above the surface of the sea. The mooring structure extends around a central area to generally enclose that area to form a generally enclosed sheltered harbour having at least one entrance for vessels, and the mooring structure comprises at least one hollow water-tight caisson capable of storing a liquid such as oil, gas or the like.

Description

United States Patent 3,779,024 Greve Dec. 18, 1973 STATIONARY STORAGE AND MOORING 1,423,884 7/1922 Rush 61/49 PLANT T G ON T BOTTOM O 3,492,826 2/1970 Horstketter. 61/49 THE SEA 2,071,520 2/1937 Harrison 61/4 2,939,290 6/1960 Crake 61/46.5 [75] Inventor: Gottfred Greve, Oslo, Norway 3,572,278 3/1971 Knapp et a1. 61 /46.5 X 3,488,967 1/1970 Toossi 61/46.5 [73] Assignee: A/S Hoyer-Ellefsen, Oslo, Norway Filed J 21 1971 FOREIGN PATENTS OR APPLICATIONS 1 1,413,074 8/1965 France 61/1 R [21] Appl. No.: 155,136

Primary Examiner-Jacob Shapiro [30] Foreign Application Priority Data A ym y et June 23, 1970 Norway 2442/70 [57] ABSTRACT [52] US. Cl. .l 61/46 [5 I] In CI E02, 17/00 Eozd 5/00 B63) 35/02 A stationary plant for servicing ships comprises a l 58] Fi d a h 61 M 50 52 mooring structure resting on the bottom of the sea and e e W projecting upwardly above the surface of the sea. The mooring structure extends around a central area to generally enclose that area to form a generally en- [56] References cued closed sheltered harbour having at least one entrance UNITED STATES PATENTS for vessels, and the mooring structure comprises at 3,630,161 12/1971 Georgii 6 l/46.5 least one hollow water-tight caisson capable of storing 3,618,327 11/1971 Frein et al. 61/34 a liquid such as oil gas or the 3,660,954 5/1972 Logan 52/309 3,563,041 2/197! Michel 61/46 11 Claims, 2 Drawing Figures o at o l 0 /3 f o 0 o I o I ,4 4 O 12 m o 0 l O a PATENTED DEC] 8 I975 M o@ooooo ooo ooo %Mvooo STATIONARY STORAGE AND MOORING PLANT RESTING ON THE BOTTOM OF THE SEA The present invention relates to a stationary plant resting on the bottom of the sea and projecting above the sea level as well as constructed for anchoring vessels.

The new and characterizing idea forming the basis of the present invention is the idea that such a stationary mooring plant can be constructed so as to comprise storage tanks in the form of caissons or the like which are suited to receive natural raw materials as for instance oil or gas.

The invention is especially intended for use in connection with oil or gas sources in the heavy seas where the materials won can be fed directly into the storage tanks which constitute the main part of the plant structure. Tankers can then anchor alongside said storage tanks to load the oil or the gas.

In this connection it should be mentioned that harbors consisting of caissons are previously known. Said caissons, however, are filled with sand, stones or the like and form a purely structural element of a conventional wharf. The previously known structures of similar kind have only been located on moderate depths in close connection with a shore.

It should also be mentioned that storage tanks placed on the bottom of the sea are known. Said storage tanks, however, have been solely used as storage tanks having no structural features whatever to permit mooring of vessels. They have provided no protection against heavy sea, no quay, no fenders and no area for storage of goods or mounting of cranes, harbor warehouses, industrial offices, crews quarters or the like. It is, in fact, typical that storage tanks of the mentioned kind are only known from areas in smooth sea not far from the shore, where vessels can anchor without need of any harbor.

As mentioned, the present invention, on the other hand, is based on the idea that the mooring plant consists of specially shaped storage tanks. It is adaptable to any desired and conventional use of a harbor and may be positioned and served satisfactorily in any sea area without limitations. The plant according to the present invention will only be unsuitable economically at great sea depths.

The plant is especially useful in shallow sea areas far from the shore and in areas with much heavy weather, eg in the North Sea. In such a case the previously known storage tanks on the sea ground would be unsuitable because vessels would arrive irregularly, which again causes need for enormous storage capacity and expensive transport. A plant according to the present invention is also advantageous because of its space for crews quarters, industry etc.

If the water depth is so large that the caissons would have to be disproportionately big, the sea ground may be elevated. Thus a fill may be provided on which the caissons is placed. The fill will normally be made of stone or sand. I

To achieve the necessary stability the caissons may partly be filled with sand, stone or similar material. Out of stability considerations it would also be suitable if the caissons are made reinforced concrete structures.

A caisson could advantageously be divided into several smaller cells or in other words: several caissons can be assembled to a large caisson. The sides exposed to waves are formed in such a manner that the waves are 2 broken down or subdued. This is especially the case on the water level. For instance a corrugation, a grill or a series of piles could be provided.

The invention will now be described with reference to an illustrating embodiment shown in the drawing, where FIG. 1 shows a perspective plan view of a plant according to the invention, arranged as a partly closed harbor, and

FIG. 2 shows a section along the line A--A in FIG. I.

1 is the mooring structure built of caissons 2. The latter are partly constructed as storage tanks for oil 3 and partly as chambers for sand 4. Interior walls 5 divide the caissons into cells and 6 is a cover dividing the spaces for oil and sand. 7 is a stone fill arranged to elevate the bottom of the sea below the caissons. The partly closed harbor basin provided by the embodiment according to FIG. 1 is marked 8. Here vessels 9 can find lee shelter. The deck 10 can be used for manufacturing premises, crews quarters, helicopter deck or the like. The portion of the mooring structure exposed to waves is preferably made in such a manner as to subdue or break the waves. Such means may include corrugations 11. In addition, piles, grills or the like indicated as 12 in FIG. 1 may be provided at a distance from the mooring structure for breaking down the energy of the waves before they reach the mooring structure. The top of the mooring structure 1 would preferably include at least one flat portion adapted to-serve as a helicopter deck, a helicopter being indicated schematically at 13 in FIG. 1. The concrete walls of the storage tanks are preferably finished with a plastic coating.

It will be understood that the embodiment of the plant according to the invention shown in the drawing and described above is only intended as an illustration of the inventive idea, and can be varied in many ways within the scope of the invention. It is essential that storage tanks are arranged in such a manner that a suitable mooring possibility is provided, which is adapted in each case to the desired storage capacity, protection against heavy weather, quay area etc.

I claim:

1. A stationary plant for servicing ships comprising:

a mooring structure resting on the bottom of the sea and projecting upwardly above the surface of the sea, said mooring structure extending around a central area to generally enclose that area to form a generally enclosed sheltered harbor having at least one entrance for vessels, said mooring structure comprising at least one hollow water-tight caisson capable of storing a liquid such as oil, gas or the like.

2. A plant according to claim 1, said mooring structure being constructed from its bottom to its top of a plurality of individual caissons forming a plurality of cells watertightly separated from each other.

3. A plant according to claim 1, in which the outer periphery of the mooring structure exposed to waves said mooring structure resting on said till.

10. A plant according to claim 1, wherein the storage capacity of the caissons is more than 100,000 tons of oil.

11. A plant according to claim 1, wherein said at least one caisson has concrete walls finished with a plastic coating.

Claims (11)

1. A stationary plant for servicing ships comprising: a mooring structure resting on the bottom of the sea and projecting upwardly above the surface of the sea, said mooring structure extending around a central area to generally enclose that area to form a generally enclosed sheltered harbor having at least one entrance for vessels, said mooring structure comprising at least one hollow water-tight caisson capable of storing a liquid such as oil, gas or the like.

2. A plant according to claim 1, said mooring structure being constructed from its bottom to its top of a plurality of individual caissons forming a plurality of cells watertightly separated from each other.

3. A plant according to claim 1, in which the outer periphery of the mooring structure exposed to waves includes means for breaking down the waves.

4. A plant according to claim 3, wherein the means for breaking down the waves include a corrugated surface on the outer periphery of the mooring structure.

5. A plant according to claim 1, including a means provided at a distance spaced outwardly from the mooring structure for breaking the energy of the waves before they reach the mooring structure.

6. A plant according to claim 1, in which the caisson is at least partially filled with sand, stone Or the like.

7. A plant according to claim 1, wherein the plant is arranged as an island in open sea.

8. A plant according to claim 1, wherein at least a portion of the top of the structure is generally flat, and is constructed as a helicopter deck.

9. A plant according to claim 1, including a fill of stone, sand or the like on the bottom of the sea, and said mooring structure resting on said fill.

10. A plant according to claim 1, wherein the storage capacity of the caissons is more than 100,000 tons of oil.

11. A plant according to claim 1, wherein said at least one caisson has concrete walls finished with a plastic coating.

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